ive gotten any where from 19.5 to 21.7 i fill her up to the brim drive 600 miles and fill her up to the brim again and divide the gallons put in by the 600 miles. Ive checked it on 6 different fill ups in the past 3 months and the lowest was 19.5 and the highest was 21.7. Its been goin up with the mods i keep doin. I drive mostly country roads and 5 days a week i drive into town and back for work. I also put in the diesel additive from walmart in the grey bottle.

 

does the additive do anything ?

 

dont know i always put it in, but they claim cleaner injectors and better economy, for the most part it puts lube back into the diesel.

 

Alot of the mod's I've done actually increased my mileage.

 

sweet ... i just may have to try the additive do you put one in per tank ? or every other or so ?

ya from what i have been hearing from a few friends is that with a intake and exhaust it should help my mpg

 

16 around town to about 22 highway with my automatic. I run an additive most of the year and when the cruise control is on I think I might get a little better than 22 on the highway. K&N filter and no exhaust past the cat.

 

thats not unbelievable many performance upgradesalso help with mpg as long as you can keep your foot out of it (which can be very difficult)
as it is more efficient .. i read about an 700 hp cummins getting 40 mpg in diesel power or diesel world . one of those not sure

 

around town i get 20 and pure high way in the texas hill country i can get 26 driving with 10 psi and no more

 

it makes sense how more hp will increase your mpg ...just have to find that pwr to wght sweet spot .. ... well i just orderd a #5 plate for my truck and and gettin ready to build a filter and do a straight pipe from the cat back and that should probly help me out ... but i mostly run hiway all the time

 

I know this is old but what did your mods result your mileage in